Many trucks having raised beds include a manually releasable or powered latch for the tailgate door and hydraulic cylinders for pivotally raising the door to an open position. After dumping, the door is then pivotally lowered to a closed position and manually locked. In such pivoting tailgate doors, since the doors are hinged at the top, generally the door seal is much better at the top of the door then at the bottom where it is latched. Often, shims are used at the door hinge mounting positions to move the top of the door away from the frame in an attempt to equalize the seal around the door perimeter. Shim adjustment, however, is very time consuming, and at best, results in a degradation of the tight seal at the top of the door while providing a moderate seal around the entire door perimeter.
Therefore, it is desired to provide a hydraulically operated tailgate door which is pivotally hinged and yet can provide a tight seal around the entire door perimeter. Also, it is desired to provide a hydraulically operated tailgate door without requiring manual locking and unlocking of the door.